The invention relates generally to chiller refrigeration systems and, more particularly, to a method of maximizing the cooling capacity of the chiller refrigeration system at start-up.
In many conventional chillers, the compressor, such as a centrifugal compressor for example, is driven by a driving means, such as an electric motor for example, either directly or through a transmission. Optimum performance of the compressor is strongly influenced by the rotating speed of the compressor. The volume of refrigerant flowing through the compressor must be adjusted for changes in the load demanded by the air conditioning requirements of the space being cooled. Control of the flow is typically accomplished by varying the inlet guide vanes and the impeller speed, either separately or in a coordinated manner.
When a conventional chiller system is initially started, the inlet guide vanes are typically in a fully closed position, allowing only a minimum amount of flow into the compressor to prevent the motor from stalling. Only when the motor reaches a full speed will the system begin to open the inlet guide vanes, thereby increasing the capacity of the system. Consequently, a significant amount of time may elapse from when the chiller system is initially started until the guide vanes are fully open and the system is operating at maximum capacity. Some applications, such as data centers for example, require the system to reach a maximum capacity in a shorter amount of time than is allowable using a conventional system.